[Simh] The missing PDPs

[Johnny Billquist]

I'm almost surprised that the PDP-5 isn't already done. As far as I can 
remember, the changes needed compared to a PDP-8 is not much. PC is at 
address 0 instead of internal to the CPU, and interrupts then store the 
PC at 1, and start executing at 2.
All the rest of the CPU works the same, as far as I remember. Of course, 
there might be some peripherals to work on, which any PDP-5 software 
would be expecting...

The PDP-12 poses a more interesting problem, as it is a dual CPU thingy 
with shared memory and two totally different instruction sets, but some 
interaction between them...

   Johnny

On 2019-08-13 03:54, Ray Jewhurst wrote:
> Greetings,
> 
> Has any ever thought of writing simulators for the two missing systems, 
> the PDP-5 and the PDP-12?  I know there is documentation for both on 
> Bitsavers and software for the PDP-12 and I have seen some papertape 
> labeled for both use on the PDP-5 and PDP-8.  If I had the knowledge I 
> would try doing the PDP-5 myself but my knowledge of C is somewhere 
> between beginner and intermediate so I would not be a good candidate for 
> doing it myself but I would more than interested in either writing 
> documentation or alpha/beta testing.  I know that there wouldn't be a 
> whole bunch of practicality for either simulator but I think it would be 
> kind of neat to complete the series.  Also, I know there is at least one 
> PDP-12 simulator out there already but I couldn't get it to build.  It 
> is located at https://github.com/andysan/greenpea . Any advice, 
> suggestions or just plain criticism of this idea would be welcomed.
> 
> Thanks,
> 
> Ray
> 
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-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol